A study of the motion pivot in the spine——The measurement of the angle between the vertebra body and the inferior articular facet and its application in the spinal manipulation

spinal motion pivot, spinal manipulation, the angle of facet joint, force direction, cylinder pivot motion theory The spinal joint consists of a disc and posterior facet joints. It is the biomechanical structure that enables the spine with six (6) freedoms of movements of flexion/extension, side bends and rotations. We identified that the same spinal joints initiate, eliminate and control spinal movement. These four joints are the atlanto-occipital and the atlanto-odontoid joints, C7/T 1, T12/L1 and L5/S1. The word“pivot”is commonly used to describe an important ruruing porint or matter in Chinese language.We define the above four joints as“pivots” in this article.The joints are briefed as“Occipital-vertebral pivot”(atlanto-occipital and atlanto-odontoid joint),“cervicalthoracic pivot” (C7/T1),“thoracic-lumbar pivot” (T12/L1)and“lumbar-sacrum pivot”(L5/S1). After measuring 20 human spinal columns (dry bones), observing the angle between the vertebral body and the inferior articular faeet,reviewing the spinal anatomy and biomechanics and analyzing the Chinese spinal manipulation techniques and theory, the following is our report: